The present invention is related to risers for sprinkler heads and more particularly to such risers that provide the capability of allowing lateral deflection of a sprinkler head and for returning the head to an upright condition after such deflection.
It is a problem, particularly with fixed in place irrigation systems which utilize sprinkler risers, to prevent grazing animals from rubbing or bumping against the upright risers to bend them over or otherwise damage the sprinkler head. Such sprinkler risers are also prone to damage from vehicles being driven over the irrigated area. It has therefore become desirable to devise some form of resilient sprinkler riser that will bend in response to excessive lateral forces, but will spring back to hold the sprinkler head upright while the sprinkler is in operation.
U.S. Pat. No. 3,759,445 to Robert W. King discloses a flexible fitting for lawn sprinklers. This fitting is located below ground between a riser pipe and water supply pipe. The fitting is flexible. However, there is no designed resiliency that would tend to move the riser back to an upright condition after being deflected.
U.S. Pat. No. 555,147 to J. H. Burck discloses a flexible spraying pipe. This pipe is constructed of a flexible material such as rubber and includes an elongated expanded helical spring extending coaxial therewith along a portion of the pipe length. Both ends of the spring are fixed to the spray tube. A slidable collar is mounted to the tube below the spring and is connected by an elongated link to a radial arm protruding from the upper spring end. The lower end of the link is also connected to a radial arm of the slidable collar. The collar will slide axially along the tube in response to axial force. However, an eccentric force such as that applied through the link to the arm will tend to bind the collar in place on the tube, therefore holding the upward end in a desired configuration. The spring is therefore not resilient in the sense that it is incapable of automatically returning the water supply tube to an upright condition after the tube has been deflected laterally. The expanded or "open" helical spring alone would not hold the sprinkler head still under the normal operating forces applied by an operating pulsating sprinkler head. Instead, such a spring would deflect (even if only slightly) and upset the sprinkling pattern designed for the particular sprinkler head.
U.S. Pat. No. 2,061,987 to O. A. Sorensen discloses a spray device that, like the Burck device, utilizes an elongated flexible tube to position a spray head. The delivery tube is elongated and includes a coaxial flexible metal hose made up of interlinked annular channels. The metallic flexible hose allows selective positioning of the spray head and will hold the delivery tube in a selected angular position. No provision is made to automatically return the delivery tube to an upright position after such deflection.
U.S. Pat. No. 3,587,972 to Waldo W. Weeth discloses an irrigation system made up of a plurality of rotating flexible pipe sprinklers. These pipes do not include outside support and rely upon water pressure to maintain the flexible portion of the delivery tube in an upright condition. No provision is made, other than water pressure applied through the tube, to hold the water delivery tube in an upright condition.
It is a first object of the invention to provide a resilient sprinkler riser that is designed to deflect in response to an animal or vehicle coming into contact with the sprinkler head or riser body; and that, after such deflection, will return the sprinkler head and delivery tube to an upright condition.
It is another important object to provide such a resilient sprinkler riser that will withstand normal lateral operating forces produced by a pulsating, rotational type sprinkler head.
It is a still further object to provide such a resilient sprinkler riser that is very simple in construction and easy to install.
These and still further objects and advantages will become apparent upon reading the following description which, taken with the accompanying drawings, disclose a preferred form of the present invention.